RT Journal Article
SR Electronic
T1 Prospective Feasibility Trial of Radiotherapy Target Definition for Head and Neck Cancer Using 3-Dimensional PET and CT Imaging
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 543
OP 552
VO 45
IS 4
A1 Christopher Scarfone
A1 William C. Lavely
A1 Anthony J. Cmelak
A1 Dominique Delbeke
A1 William H. Martin
A1 Dean Billheimer
A1 Dennis E. Hallahan
YR 2004
UL http://jnm.snmjournals.org/content/45/4/543.abstract
AB The aim of this investigation was to evaluate the influence and accuracy of 18F-FDG PET in target volume definition as a complementary modality to CT for patients with head and neck cancer (HNC) using dedicated PET and CT scanners. Methods: Six HNC patients were custom fitted with head and neck and upper body immobilization devices, and conventional radiotherapy CT simulation was performed together with 18F-FDG PET imaging. Gross target volume (GTV) and pathologic nodal volumes were first defined in the conventional manner based on CT. A segmentation and surface-rendering registration technique was then used to coregister the 18F-FDG PET and CT planning image datasets. 18F-FDG PET GTVs were determined and displayed simultaneously with the CT contours. CT GTVs were then modified based on the PET data to form final PET/CT treatment volumes. Five-field intensity-modulated radiation therapy (IMRT) was then used to demonstrate dose targeting to the CT GTV or the PET/CT GTV. Results: One patient was PET-negative after induction chemotherapy. The CT GTV was modified in all remaining patients based on 18F-FDG PET data. The resulting PET/CT GTV was larger than the original CT volume by an average of 15%. In 5 cases, 18F-FDG PET identified active lymph nodes that corresponded to lymph nodes contoured on CT. The pathologically enlarged CT lymph nodes were modified to create final lymph node volumes in 3 of 5 cases. In 1 of 6 patients, 18F-FDG–avid lymph nodes were not identified as pathologic on CT. In 2 of 6 patients, registration of the independently acquired PET and CT data using segmentation and surface rendering resulted in a suboptimal alignment and, therefore, had to be repeated. Radiotherapy planning using IMRT demonstrated the capability of this technique to target anatomic or anatomic/physiologic target volumes. In this manner, metabolically active sites can be intensified to greater daily doses. Conclusion: Inclusion of 18F-FDG PET data resulted in modified target volumes in radiotherapy planning for HNC. PET and CT data acquired on separate, dedicated scanners may be coregistered for therapy planning; however, dual-acquisition PET/CT systems may be considered to reduce the need for reregistrations. It is possible to use IMRT to target dose to metabolically active sites based on coregistered PET/CT data.